Rapidly decreasing features sizes and increasing power density in microelectronic devices has necessitated development of novel cooling strategies to achieve very high heat removal rates from these devices. For example, heat removal rates in excess of 200 W/cm2 have been projected for the next generation of personal computing devices. Microchannel heat sinks have the potential to achieve these heat removal rates and therefore have been studied for over two decades as described, for example, by Tuckerman and Pease “High performance heat sinking for VLSI”, IEEE Electron Device Letters, Vol. EDL-2, pp. 126-129, 1981, and by Garimella and Sobhan “Transport in microchannels-A critical review”, Annual Review of Heat Transfer, Vol. 14, 2003. However, the high pressure drops encountered in microchannels have largely precluded their use in practical applications thus far. In particular, such microchannel heat sinks require an external pump to drive the fluid through the microchannels. The need for an external pump is quite disadvantageous in that relatively large amounts of electrical power and space would be needed for the pump.
Moreover, micropumps are being developed for delivering drugs, medicines or other treatment agents to patients. These micropumps require controllable rates of fluid flow to deliver exact amounts of a drug, medicine or other treatment agent to the patient.